Iíve been wondering what causes a groove to wear in the claw washer, as named in FSMs, that butts against the outer wheel bearing in the front axle hub or a full float rear axle hub. If the bearing is in good condition, pre-tensioned and lubed properly what would allow the wheel bearing cage to rotate against the washer, creating the groove, instead of the bearings within the cage moving as they should? Any thoughts?
Thanks

I wonder as well and look forward to the experts chiming in...I did a full front axle service on the LX in Oct '09 and had what I thought was loose front bearings the following summer. Pulled it apart and both claw washers had slight grooving on them (they were new) but not the bearing. Replaced them and tightened everything back up but I still had the noise. Thinking the noise now is the front DS. But, I think since everything up front was new (races, bearings, etc.) on my rebuild that I should have gone tighter on the preload initially as it seems common for new stuff to have a tendency to loosen up after a bit.

My guess is that you think you got the bearing preload correct but in the end it wasn't enough which allows the bearing cage to spin. The other possibility I've seen is what Nakman had and that was the worn spindle which not matter what wouldn't allow the correct preload. I'm preload challenged though and can't ever seem to get it right. I'll redo it 20x and still doubt myself. Some don't follow the FSM at all and set the preload a lot higher (like 2-3x as high) than what the FSM states with seemingly no ill affects.

My thinking is that it happens most often when the nut bottoms out before a high enough force is put on the bearing & races to set them. I also wonder if it could happen when the outer races are not seated straight or fully.

My guess is if anything is off or goobered, then the bearings can get cockeyed ('specially before they wear in) and maybe spin when the grease is really cold, for example like when it's -19F...

I'm only being a little sarcastic, when it's butt-ass cold metal shrinks, grease is uber thick, it would not surprise me if more than a few times a marginally set wheel bearing has spun a couple of revolutions before warming up enough to stay put. It only takes a couple of times to groove the washer or wear out the spindle and then it happens easier the next time.

just wondering if this could have something to do with the type of grease in the bearings? as in moly grease vs lithium for the bearing? I was just going to pick up grease for my birf repack and noted there was different grease suggested for wheels bearings vs birfs.

Martin, I know several people who swear by Amsoil's moly grease in every application. I don't abide by this notion and use moly grease in the birfs while Amsoil's lithium grease gets packed into the wheel bearings as well as in the u-joints. Toyota's procedure for wheel bearing pre-loading is faithfully followed so I count out the possibility that the bearings were installed cockeyed and the races were untouched in this case so I don't think that wasn't the problem, either. The synthetic grease, #2, shouldn't have been affected by the zero degree temps the truck had seen prior to my finding the groovy claw washers. I've since flipped the washers and tightened the pre-load spec to 15 ft/lbs compared to Toyota's recommended four ft/lbs and will see what gives the next time the bearings are cleaned and repacked. I have yet to read anything that might definitively explains the claw - thrust - washer wear.

Well I have commented about this on Mud before. Here how it goes, the wheel bearing slightly wears all the time, on a new spindle the inner race is a slight press fit and this keeps the inner race tight to the spindle. Once wear happen on the races, preload is no longer between the inner and outer bearing. So no preload, no pressure on the inner race, and when that happens, any slight de-bree or heat or turning will allow the race to spin. once it spins it wears the spindle. the quicker the wear gets worse. Hence the groove in the thrust, it is from the outer wheel bearing inner race spinning.
So most people do not check there wheel bearing often enough(Toyota use to spec checking the wheel bearings at 15k intervals for stock tires and rim combo). Repacks came at 30k intervals. With people going to bigger tires and wheels, more aggressive tire patterns, more stress. I believe one should be checking for bearing looseness when you change your oil or sooner(if you believe in 10k oil intervals) at 5k intervals.
If loose tighten it. I do believe that one thing that makes it worse is the thrust is soft. If one looks at all the Toyota rear full floater, they use a different type of thrust and it is of hardened material, instead of the soft stuff in the front. They stay tighter longer with less inner race wear.
So most of us do not get brand new spindles very ofter (Not at 250 a pop). So we do not do much about what is going on. Well there is a technique called staking the spindle to raise the metal so the inner race will adhere to it a bit. I use a pin punch to put little dots in the metal, these little dots raise the metal a bit. I usually do it in a even pattern
around the spindle, usually using 6-8 dots. do not hit the punch too hard, you do not want to raise the metal too much.
Again most people do not know how to tighten the nuts to a proper spec. Even with the book way, the bearing can be too tight or too loose. See the book does spec's with a fish scale and torque spec's these can only be good if you are at the right temp and use the exact same grease. I have been doing it a different way for a long time. I use a new thrust every other time, I start with a flat surface. I turn this surface on to the inner race. I do a bearing preload run( I put a lot of force on the wrench and nut), spin the hub back and forth. If I can not spin the hub with some effort, I have not gotten preload enough. I then back it off about 1/2 turn. Tighten the nut up again. With a pry bar about 8-10 inches I pry the thrust back and forth(or try to). If I can not shift the claw washer from side to side with some effort, I know it is too tight. but the trick is to find how much force it takes to move the thrust from side to side. Once I have found the sweet spot, I then put a new lock star washer on, then the nut. I tighten it to about 45 lbs(or my feel of it). I never lock the top lock on the star washer, it could pull the little tag out of the groove and allow the lock washer to move.
Anyhow, this is just my way of doing things and what I think happens.
Really, any spindle wear should mean a new spindle, staking is a way to prolong the life of a part until you can afford a new part.
The only way the adjusting nut can bottom out, is excessive wear in the bearings, or too much spindle wear where the inner race of the inner bearing has been spinning too much and has worn off the shoulder of the support for the bearing.

I forgot to comment on Grease. I use a high precentage moly in the birf's(at least %3 or more, most moly grease on the shelf is about %1 moly). I then use High quality lithium wheel bearing grease for the hubs. I also do not believe that Moly should be used in wheel bearing any more.

Thanks for your insight here Robbie. At 15 ft/lbs of torque on the inner adjusting nut, I was able, with some effort, to get the thrust washer to move a small bit when prying with a screwdriver before installing the star washer and lock nut. Not bending the tab on the star washer onto the outer lock nut is something I don't remember hearing about before. I'm not following your description of the star washer tab moving (stripping?) out of the hub groove and allowing unwanted movement. Would you elaborate, please?
Thanks.

These tabs are not real tight to the spindle, I have pulled many apart that were oval not round any more. I think this is from the metal pulling outward when the tab is bent.
Well when you bend that top tab over, it has the potential to pull the tab higher into the groove. When that happens, both nuts and the lock tab can spin and back off. It is like mechanical leverage when bending this tab over. I have made it a habit not to bend this tab over.
I like bending the lower tabs over thus pulling the lock washer deeper into the groove. I know it may sound trivial, but mechanical forces do apply when bending metal even if locked between two nut, movement can occur.
Does that help explain it Steve?

These tabs are not real tight to the spindle, I have pulled many apart that were oval not round any more. I think this is from the metal pulling outward when the tab is bent.
Well when you bend that top tab over, it has the potential to pull the tab higher into the groove. When that happens, both nuts and the lock tab can spin and back off. It is like mechanical leverage when bending this tab over. I have made it a habit not to bend this tab over.
I like bending the lower tabs over thus pulling the lock washer deeper into the groove. I know it may sound trivial, but mechanical forces do apply when bending metal even if locked between two nut, movement can occur.
Does that help explain it Steve?

Genuine food for thought, Robbie, and I thank you for taking the time to describe the situation in a way that we can all understand. It's fun stuff like this that keeps us involved in Cruiser tech and our trucks on the road. The engineers that created our vehicles have an understanding of complex design, but, at the same time, have been able to keep things simple enough that you don't have to be a rocket surgeon to understand the complexities. Robbie, your combination of real world knowledge and experience seems to be right in the middle between us "users" and the "designers" that develop the trucks we love so much. Thanks for giving us things to ponder.